Wall lining of industrial ovens

ABSTRACT

The invention relates to a wall lining of industrial ovens for protecting from corrosion, in particular, a heat-resistant wall made of concrete, steel, sheet metal, or the like. The lining of the wall is made of at least two layers, wherein a layer is pressurized as a blocking layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the priority filing date in PCT/EP2008/009856 referenced in WIPO Publication WO/2009/080167. The earliest priority date claimed is Dec. 22, 2007.

FEDERALLY SPONSORED RESEARCH

None

SEQUENCE LISTING OR PROGRAM

None

STATEMENT REGARDING COPYRIGHTED MATERIAL

Portions of the disclosure of this patent document contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office file or records, but otherwise reserves all copyright rights whatsoever.

BACKGROUND

The invention concerns a wall lining for industrial ovens for protection of wall components from corrosion. The wall structure can be stratified of concrete, steel, sheet metal and/or similar heat resistant layers.

In industrial applications, ovens are installed, which are enclosed within high temperature resistant materials. In the operation of such ovens, interior temperatures may exceed 1000° Celsius (hereinafter “° C.”). The heat-resistant walls of such ovens are exposed to the environment on the outside and exhibit a surface temperature substantially less than that of the interior. At a general room temperature of 20° C., the outer wall temperature may be, for example, 60° C., while the interior wall exposed to the operating temperature stands between 400 to 900° C. The high-temperature resistant material, of which the oven wall is composed, is thus subjected to extreme variances in temperature. Under these conditions a danger exists, that fissures can form in the wall material.

Thus a problem arises that aggressive gases arising within the oven can migrate through such fissures and attack the positioned layers and casing in the wall. The result is that a debilitating corrosion occurs.

The present invention has the purpose of protecting the wall of an oven from such destructive corrosion, wherein the wall is composed of concrete, steel, sheet metal and/or similar heat resistant materials.

This purpose is achieved, in accord with the invention, in that the construction of the wall consists of at least two layers, wherein one of the layers is a pressurized air, predetermined sized enclosure.

Especially highly recommended types of invented wall construction are described and explained in subordinate claims.

Advantageously, a mechanical binding exists between layers which successively form the wall. The most inner of the layers consists of heat-resistant material such as a high-temperature resistant material or concrete (hereinafter referred to as “refractory”), which is fastened in place by metallic anchors or similar steel fasteners. The blocking layer holding pressurized air, as described below, is found between this inner refractory and an outer steel casing. The invented, pressurized, blocking layer can also be placed between an insulation layer and the refractory layer, whereby, fissures in the refractory material lead aggressive gas to engage the blocking pressurized layer. Unlike the aggressive gas from the oven, the pressurizing medium is inert and is normally air. The feeding of this pressurizing air is accomplished with known means, while the pressure and flow thereof are controlled by standard methods.

Advantageously, the pressurized air layer can be filled with a porous material. That is to say, the filling could be comprised of a ceramic fiber or a foamed substance. In this way, the achievement is gained, first, that a pressurized, air filled blocking layer is obtained, which repels the attack of corrosive gas, and second, by means of the mechanical stability of a highly porous layer, the required mechanical binding between the layers is assured.

In accordance with another especially recommended method of construction, protrusions, at predetermined intervals, extend themselves from the refractory layer to penetrate the pressurized, air filled blocking layer. These protrusions assure that a known spatial interval exists between the support points within the blocking layer, whereby, again, the required binding between the layers remains intact. Additionally, as described below, metal anchors are advantageously arranged, that the surfaces of the above-said metallic anchors subject to corrosive attack are enveloped in a flow of moving, inert air.

In the case of an additional, especially highly recommended method of construction, the metallic anchors, which serve for fastening the lining, protrude through the pressurized blocking layer. They are coated with a substance which will change its properties when subjected to operational temperatures. This change can include one or more of the following states: melting, burning, softening, shrinking, contracting, sublimation, evaporation, or slowly vaporizing.

This material accordingly disappears at operating temperatures leaving a void, so that the pressurized air can enter and envelope the anchoring. In this way, the anchors are better protected from the corrosion of aggressive oven generated gases.

In accordance with another preferred embodiment, the blocking layer has the character of at least a single enclosed chamber, filled with pressurized air. In this embodiment, a closed space exists between the described high temperature lining and the casing which can be filled with pressurized air. In the case of this arrangement, no mechanical binding between the layers is necessary.

In many industrial processes, operating ovens possess a sheet metal casing. In accordance with the invention, this casing is designed to be protected with at least one layer of heat resistant material, whereby, between the heat resistant material and the sheet metal, at least one layer of pressurized air is present. This now blocking air layer considerably obstructs the progress of aggressive gas toward the sheet metal casing.

DRAWING

FIG. 1: displays a cross section of the invented high temperature wall construction.

DETAILED DESCRIPTION

The casing 1 is sheet metal. This casing 1 encloses three layers of the wall, namely, in order from the oven interior outward: a refractory layer 4, pressurized air layer 3 and the insulating layer 2. The refractory layer 4 is composed of a high heat resistant material 5, which is fastened to the outer casing by metallic anchors 6. Between the refractory layer 4 and the casing 1, is a pressurized air layer 3 and an insulation layer 2. The blocking layer 3 is supplied with air by an inlet tube 7 so that chamber 3 advantageously becomes pressurized. This blocking layer can remain either empty or may be filled with a highly porous material. In either case, the layer is subjected to pressurized air. In this blocking layer 3, projections 8 are aligned, spaced at predetermined intervals. These determine the width of the open spacing between the casing refractory layer 4 and the insulation layer 2. The interval projections 8 protrude from the refractory material 5 of the refractory layer 4. The metallic anchor 6, with which the refractory layer 4 is stabilized onto the casing 1, penetrates through the blocking layer 3 as well as through the insulation layer 2. These metallic anchors 6 can be encapsulated in a selected substance, which change characteristics in the presence of operating temperature, such as: melting, burning, softening, shrinking, contracting, sublimation, evaporation, or slowly vaporizing. This temporary encapsulation material disappears at operating temperatures, leaving an empty space, so that the protective air, being pumped into the blocking layer 3 can flow about these anchors, thus protecting them from corrosion.

In the presentation of FIG. 1, the interior space of the oven is located above the refractory layer 4. In this interior 9 of the oven, the operating temperature can run as high as 1000° C. The casing 1 is exposed, on its outside to the room temperature, that is, approximately 20° C. The stated temperature differential between the inner and the outer sides of the wall is frequently the cause of fissures and deterioration in the material 5 of the refractory layer 4. These fissures in the refractory layer 4 make it possible for the passage of aggressive combustion gas to migrate in an unrestrained manner out of the interior of the oven 9 and through the refractory 4 and insulation 2 layers, thus corrosively attacking the casing 1. By means of the pressurized gas in the blocking layer 3, a barrier is put in place to prevent the progress of aggressive gas through fissures in the refractory layer 4 and through the insulation layer 2 to reach the casing 1. 

1. A wall lining for industrial ovens for the protection of an oven wall constructed of high temperature resistant materials, including concrete, steel, and sheet metal, characterized in that the wall lining consists of at least two layers (4; 3), wherein a blocking layer 3 serves as a blocking means and is comprised of pressurized, non-reactive gas, normally, air.
 2. The wall lining according to claim 1, wherein, between wall layers (4; 3; 2), a mechanical binding occurs.
 3. The wall lining according to claim 1, wherein the blocking layer (3) has a filling of porous material within pressurized air.
 4. The wall lining according to claim 2, wherein the blocking layer (3) has a filling of porous material within pressurized air.
 5. The wall lining according to claim 1, wherein projections (8) protrude into the blocking layer (3), at predetermined spatial intervals to establish the distance between the blocking layer (3) and other layers (2; 4).
 6. The wall lining according to claim 2, wherein projections (8) protrude into the blocking layer (3), at predetermined spatial intervals to establish the distance between the blocking layer (3) and other layers (2; 4).
 7. The wall lining according to claim 3, wherein projections (8) protrude into the blocking layer (3), at predetermined spatial intervals to establish the distance between the blocking layer (3) and other layers (2; 4).
 8. The wall lining according to claim 4, wherein projections (8) protrude into the blocking layer (3), at predetermined spatial intervals to establish the distance between the blocking layer (3) and other layers (2; 4).
 9. The wall lining according to claim 1, wherein mechanical anchors (6) distributed throughout the blocking layer (3) are encapsulated in a material, which, when subjected to operating temperatures assumes one or more of the following characteristics: melting, burning, softening, shrinking, contracting, sublimation, evaporation, or slowly vaporizing.
 10. The wall lining according to claim 1, wherein the blocking layer (3) is designed as at least a single closed chamber, which is pressurized by an inert gas, normally by air.
 11. The wall lining according to claim 1, wherein the wall possesses a sheet metal casing (1), which is provided with an inner structure, comprising a layer (4) of a refractory material (5) and between the layer (4) of the refractory material (5) and the sheet metal casing (1) is at least one chamber (3) serving as a blocking, pressurized layer of air. 